1. Field of the Invention
The present invention relates to a diamond cutting method, enneahedral-cut diamonds and an assembly of enneahedral diamonds. The enneahedral-cut diamond has a square or rectangular table with eight facets defining together a pavilion.
2. Related Arts
A diamond of the finest cut with 58 facets is well known as a brilliant cut. Japanese Patent H9-1105A shows a brilliant cut whose unique girdle shape is claimed for patent.
The brilliant cut needs to have a regular octagonal table, which regular octagon is defined by: drawing a straight reference line passing through the center of a given circle; drawing another reference line passing through the center of the circle to be 90 degrees apart from the first reference line; drawing a 45 degree-inclined line in each quadrant of the circle; drawing a circle to define the table; and drawing chords to connect two intersecting points on the circle. Bezel facets and upper-girdle facets (33 facets in total) are formed between the table and the girdle of the gemstone.
The pavilion underneath the girdle has lower-girdle facets and lower-main facets (25 facets in total) formed in the areas divided by the keel lines starting from each corner of the regular octagonal table and converging to the culet of the pavilion.
The brilliant cut has the following proportion: the diameter of the girdle is 100%; the height is 60.4%; the diameter of the table is 55%; the thickness of the crown is 15.4%; the depth of the pavilion is 43%; the inclination angle of the crown is 34 degrees and the inclination angle of the pavilion is 41 degrees (A.G.S. Proportion Standard).
The brilliant cut causes an incident light rays to be diffused inside, not producing a single clear reflected light at an established angle of view. The cutting is a very elaborate and time-consuming work because of the large number of facets and the complicated arrangement of the facets, which is one major cause for the expensiveness of brilliant cuts.
Such brilliant cuts can be set on an object, but cannot be structurally combined as a whole.